Creating a generic function for objects of different classes

Question

How might I refactor this to get rid of all the if-else?

  def self.dispatches_for(object)
    scope = Dispatch.asc(:days)
    if object.class == Habit
      scope.where(:habit=>object).map{|d|d}
    elsif object.class == User
      scope.where(:coach=>object).map{|d|d}
    elsif object.class == Content
      scope.where(:content=>object).map{|d|d}
    end
  end

Answer 1

def self.dispatches_for(object)
  klass = object.class.to_s.downcase.to_sym
  raise "unacceptable class" unless klass.in? [:habit, :coach, :content]
  scope = Dispatch.asc(:days)
  scope.where(klass=>object).map{|d|d}
end